Key difference: White gold jewelry has become quite popular over the last few decades. This is mainly because it has the look of platinum and titanium, however costs much less than those metals. White gold is usually coated with rhodium, which gives it a nice shine. In its pure form, platinum is a soft metal and hence is very malleable, similar to gold. However, unlike gold, platinum is very heavy, up to one third heavier than 18 karat gold. Platinum costs approximately twice or two and a half times as much as gold, depending on its purity.

Gold is a pure element that is mined out of the earth. Since ancient times, it has a great monetary value assigned to it, due to its appearance, rare availability and symbolic value. It is famously used for jewelry, but also has practical uses in dentistry, electronics, and other fields as well. It is known for its high malleability, ductility, resistance to corrosion and chemical reactions, in addition to conductivity of electricity, which has led to many uses of gold, including electric wiring, colored-glass production and even for edible gold leaf.

Pure gold, as mined, is yellow in color and is relatively soft. However, this softness can be a disadvantage especially to jewelers, who need the metal to hold its shape and for any gem placing. Hence, gold is alloyed with other metals. This affects the color of the gold in addition to its hardness. The most common type of gold is the yellow gold we wear which is alloyed with zinc. Another is white gold, which has gained popularity over the last few decades. It is alloyed with silver, palladium or nickel, however, usage of nickel has reduced drastically, as many people are allergic to it. Gold is also available in tones of green, red, blue, purple and black.

Gold is commonly graded in karats. The karat tells how much alloy of other metals is used. The pure gold is 24 karat (K) which is 100% gold, 22K is 92% and 8% alloy, 18K is 75% gold, 14K is 58%, 10K is 41% and 9K is 38%. The same karat of gold will contain the same proportion of gold irrespective of its color, i.e. 18K yellow gold and 18K white gold will both be 75% gold and will contain 750 parts gold per thousand parts.

White gold jewelry has become quite popular over the last few decades. This is mainly because it has the look of platinum and titanium, however costs much less than those metals. White gold was originally designed to create something different in the wedding rings, as there was no other option at that time, rather than yellow gold. Due to the silver or palladium, white gold tends to be more durable, harder and more scratch resistant than yellow gold. White gold is considered to pair well with diamonds, which makes it popular as wedding and/or engagement rings.

White gold is usually coated with rhodium, which gives it a nice shine. This is mainly done as white gold appears as light gray in actuality. The rhodium makes it appear brighter and more silver, the appearance that white gold is famous for. The disadvantage of this is that rhodium tends to wear off eventually, so one needs to get the jewelry re-plated.

Platinum is also a pure element mined out of the earth. The name, ‘platinum’ is derived from the Spanish term ‘platina’, which means "little silver." This is mainly because of the metal’s appearance. It is a dense, malleable, ductile, very precious metal, with a gray-white appearance, similar to silver. The metal is generally non-reactive and is very resistant to corrosion. It is one of the rarest metals in the Earth's crust and hence, is quite expensive. Platinum actually costs approximately twice or two and a half times as much as gold, depending on its purity.

In its pure form, platinum is a soft metal and hence is very malleable, similar to gold. Pure gold and pure platinum can be scratched with a fingernail. However, unlike gold, platinum is very heavy, up to one third heavier than 18 karat gold. In jewelry, platinum is used in almost its pure form, usually 90% to 95% pure. The rest is usually iridium or ruthenium.

The purity of platinum is graded by a sterling number. The sterling number represents parts per thousand of pure platinum. Hence, .900 sterling is 90% platinum, .950 sterling is 95% platinum, etc.

Unlike white gold, platinum is naturally white in color, hence it does not need to be alloyed with another metal for its color. Still, white gold is more whiter and shiner than platinum, as it has rhodium plated. Platinum, on the other hand, tends to have a dull white or dull grey color, which may get darker or duller over time depending on the intensity of use. However, this can easily be remedied by a little polishing.

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